The present invention is a multi-speed drive accessory for a tool. More specifically, the present invention is an accessory or supplemental device for selectively providing multiple speed outputs for a tool such as a wrench.
Generally speaking, a single function is usually found in the operation or application of an ordinary wrench having a hexagonal head. No matter whether it is a hexagonal wrench, a shifting wrench or a universal wrench, when is revolved for one circle, the screw will also revolve for one circle. Therefore, such ordinary wrenches are found to lack a rapid assembling or disassembling function. As a solution electrical or pneumatic automatic wrench is invented. Although an automatic type of wrench can achieve a rapid assembling or disassembling function, it will be of no effect if the screw happens to be disengaged with the thread or frozen as a result of rusting since its torque force is not variable and other methods such as the use of a lever, or raising its temperature by heating to produce an expansion/shrinkage effect of unfixing the screw will have to be employed. Therefore, it is concluded that defects are inevitably found in various kinds of tools, particularly when such tools are lacking of any supplementary device that makes perfect work quite impossible.
In view of the aforementioned defects, the inventor has devoted himself in a continuous research and renovation, and managed to successfully develop a multi-speed controlled accessory or supplemental device for a wrench, by means of which a more perfect work can be achieved.